This invention relates to electrical signal coupling devices, and more specially to a signal splitter for use with radio frequency signals in the hf, vhf and/or uhf bands. The invention is more specifically directed to an improved coupling device which can be used for TV signals over the entire band of television broadcast and cable channels, to wit, in the 5 MHz to 1000 MHz range.
Generally, a line splitter is a device for connecting a signal input source to a plurality of signal output transmission paths, which can be coaxial cables destined for separate RF or television receivers. The line splitter is intended not only to match the input to output impedances, but also to isolate the output branch transmission paths from one another.
A number of line-splitters or signal-splitters have been previously proposed, for example, in U.S. Pat. Nos. 3,454,905; 3,349,345; 3,673,517; and 3,500,252. These signal splitters are typically autotransformers that have one or more ferromagnetic cores with a pair of windings formed on each core. One pair of windings is considered an input or impedance-matching device, and the other with its associated core is considered an output or splitting device.
In state-of-the-art splitters, the windings are formed of wires that pass through and around the cores to form toroidal windings of one or more turns. Typically, four bare-wire ends, one from each of the four windings, are twisted together to form a single junction. The other ends of the wire coils or windings are connected to a signal input and to ground, and first and second signal outputs.
Because this junction has four wire ends bundled or twisted together, rather long leads are required. There has been no means proposed to avoid the band-width limiting disadvantage of long leads from the splitter coils and impedance matching coils.